Sustainable bioeconomy transitions: Targeting value capture by integrating pyrolysis in a winery waste biorefinery

Abstract

In the transition to a sustainable Bioeconomy, pyrolysis-based bioenergy is finding a new impetus within integrated biorefinery concept, which is one of the vehicles of this transition. An integrated winery waste biorefinery is proposed in this study. A closed-loop approach was designed, by integrating pyrolysis process, to the primary pomace (winery waste) biorefinery. The results of the experimental study revealed that from 15 t of fresh grapes of the special variety ‘Xinomavro’ harvested per hectare in Northern Greek vineyards, along with the 10.5 t of red wine (main product), 0.27 t of hydrocolloids and 0.06 t of grape-seed oil can be produced, via pomace extraction. By pyrolyzing the remaining solid wastes derived from pomace extraction, in the secondary biorefinery, 0.52 t of biochar, 0.80 t of bio-oil and 0.630 MWh energy, can be produced. It was resulted that pyrolysis of the primary biorefinery wastes brings many benefits: it increases the number of the biorefinery products to 5 by shifting from a mono to multi-product pathway, creates an additional economic benefit of 4470€ ha−1 and avoids 355 kg CO2/t on dry pomace basis. The pyrolysis biochar can be used as a soil improver, because it contains N, P, K, Ca nutrients, significant amounts of K, Na, Mg, Ca, P, Fe, Zn, and negligible amounts of heavy metals. With the present study at TRL 4, protocols for the winery waste-biorefinery processes were created and a pathway for sustainable waste management, in the wine industrial sector, with environmental and socio-economic benefits, was provided. Pyrolysis-based bioenergy production integrated in the biorefinery was studied, as a paradigm for the greater integration of bioenergy into the Bioeconomy. Within the wider Bioeconomy transition, it is important to move from sustainability debate into sustainable solutions, and bridge the gap between research and industrial implementation.